html{
  font-size: 10px;
}
html, body{
  margin: 0;
  padding: 0;
  font-family: sans-serif;
}
.keys{
  display: flex;
  min-height: 100vh;
  justify-content: center;
  align-items: center;
}
.key{
  border-radius: 0.5rem;
  border: 0.4rem solid #000;
  margin: 1rem;
  width: 10rem;
  font-size: 1.5rem;
  padding: 1rem 0.5rem;
  text-align: center;
  background: rgba(0, 0, 0, 0.4);
  color: #fff;
  text-shadow: 0 0 0.5rem #000;
}
.key > div {
  font-size: 4rem;
}
.sound{
  font-size: 1.2rem;
  text-transform: uppercase;
  letter-spacing: 0.1rem;
  color: #ffc600;
}

